You are talking about online shopping not marketing. If you know and understand what "marketing" stands for, then you will know that it is about advertising and online shopping is really far from it. And ones you got a very good result that will make you a lot of money and you can use your profit for buying goods and anything you want.
These all are fame because of this advertisement only. Internet marketing is trend to make everything familiar to most of the people in cities. Many stretegy been follow to make and be number via Youtube, Google Adsense, SEO, SEM and etc...
I think he is simply confuse with the Ecommerce and Internet marketing. Instead make him clear and you are explain him a online good purchase platforms again.
This thread is for internet marketing so we need to clear it but all you had mentioned are good ways to do internet marketing. But don't forget that social medias are very powerful nowadays because most of the people now are staying 10+ hours on those sites just for socializing with their virtual friends and reads a lot of status of people.
That can increase your sales or revenue of your are promoting a CPA or product you can do SEO instead.
Social medias can be used for many things in advertising. It's a double purpose for those people that has seo purposes. Since it is one of the most effective way of doing everything you want. There are people that are earning enough from using it.
Yeah, indeed it is today most people use social media to promote a product they have. Because of the nature of social media is one of the places that give you a free advertising and paid well, but the main thing we must have is the uniqueness or a value from the same product out there. Because it is a value added will make someone the more interested and if indeed it is suitable, that person could be a valuable asset